/* css reset */
html{
    font-size: 10px;  /*css inhert*/
    background: url('./damn.jpg') bottom center;
    background-size: cover;
}

html, body{
    height: 100%;
}

.keys{
    display: flex;  
    align-items: center;    /*在flex容器中垂直居中其子元素*/
    justify-content: center;    /*在flex容器中水平居中其子元素*/
    min-height: 100%;
}

.key{
    border: 4px solid #000;
    border-radius: 5px;
    margin: 10px ;
    padding: 10px 5px;
    font-size: 25px;
    /* 过渡动画 */
    transition: all .3s ease;
    width: 100px;
    text-align: center;
    color: rgb(241, 244, 248);
    background: #d6dbdbc9;
    text-shadow: 0 0 5px black;  /*立体感*/
}

.key .title{
    font-size: 40px;
}

.sound{
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: #2e40e1;
}

.playing{
    transform: scale(1.1);
    border-color: #70e278;
    box-shadow: 0 0 5px #7270e2;
}
